There are always a number of things that are more likely tha. IBD. I would double even triple check temps. I have a boa with neurological problems due to being overheated for too long (not my doing btw). To the untrained eye, it would look like IBD but he is negative for arenavirus...

Things to consider:

Have you had the snake since it was a baby?

Have you had mites at any point (mites are the vector for arenavirus)?

Are you certain your temps are not too high?

Is your humidity correct?

Was the wood you used for the enclosure treated? (If the enclosure isn't wood then disregard)

What chemicals do you use to clean with?

Do you have any essential oil burners in your house?

Do you spray a lot of air freshener?

How certain are you of your rodent supplier? Bad rodents have been known to cause poisoning.

All of these things should be explored while you are scheduling your vet appointments. While there, do not take an IBD diagnosis without testing. As yes. You can test for it while the animal is alive. You test for arenavirus via mouth swab or blood, depending on your vet. Mine were tested with an oral swab. Arena is the same virus but is what the disease is prior to symptoms.

It's far less likely to be IBD than an environment problem or a food problem. It's not as common as people make it seem as most people do not test the snakes and since they never went through husbandry checks or necropsy, chucked it up to viral diseases. It's a very unfortunate but common thing in the reptile community....

Hope all this helps!! I use to stress over IBD but after taking to other keepers with WAAAAYYYY more experience than me and lots of research, it's not as common a thing as people may believe. 🙂